From Behavior to Circuit

Somatic Stress and External Pain

How is pain represented at the cellular level throughout the body?
We developed an in vivo two-photon spinal cord imaging system to study
how acute painful stimuli on the skin is represented in the spinal cord,
and to investigate how this representation changes in an animal model
of chronic pain.

Visceral stress and drug withdrawal

Opioid withdrawal can function as a useful stimulus for modeling visceral stress. Withdrawal from opiates can induce a wide range of adverse effects, including emotional effects — such as anxiety, depression, and irritability. to avoid these negative symptoms, people addicted to drugs will often continue to use.

We identified a neural node that comprises a key part of the brain circuitry meditating withdrawal symptoms. Our work reports that the neural pathway from the paraventricular nucleus of the thalamus (PVT) to the Nucleus Accumbens (Nac) plays a critical role in the experience of opiate withdrawal.

The Video on top shows a mouse that is experiencing withdrawal-induced aversive behaviors; discomfort is apparently causing the mouse to anxiously attempt escape from the room.

The bottom video shows that these withdrawal-induced symptoms are erased when the mouse has optogenetically-restored normal transmission at the
PVT-to-nac synapse.

Social Stress and pain observation

Social stimuli can be just as powerful as the physical and chemical stimuli described above. To explore the influence of social interaction on emotional state, we study the effect of pain observation: how does observing another individual in pain affect one’s personal experience of pain?